# Exposure to heavy metals, bisphenol A, and phthalates: Implications for precocious or delayed puberty

## TL;DR

This study explores how exposure to environmental chemicals like heavy metals, BPA, and phthalates may affect the timing of puberty in children and adolescents.

## Contribution

The study provides new evidence linking specific environmental chemical exposures to delayed puberty, particularly in girls.

## Key findings

- Higher mono-benzyl phthalate levels were linked to increased risk of delayed puberty in girls.
- Exposure to a mixture of BPA and phthalate metabolites was associated with delayed puberty in both sexes.
- The study found limited evidence for a link between heavy metals and puberty timing.

## Abstract

This study examined the associations between exposure to heavy metals, bisphenol A (BPA), and phthalates and precocious or delayed puberty. This study was a cross-sectional study using the data obtained from the Korea Environmental Exposure and Health Survey in Children and Adolescents. Blood samples were collected to measure lead, mercury, and cadmium levels, whereas spot urine samples were analyzed for BPA, phthalate metabolites, and creatinine levels. Sexual maturation status was assessed using self-measured Tanner stages. Our analyses involved single- and multi-exposure binomial logistic regression models adjusted for age, body mass index, presence of siblings, urban residence, and socioeconomic status. In the multi-exposure models, we applied quantile g-computation mixture analysis to calculate odds ratios (ORs) for precocious and delayed puberty. In the study cohort of 1,424 individuals, precocious puberty was identified in 50 (3.5%) individuals, whereas delayed puberty was identified in 54 (3.8%) individuals. In the single-exposure models, a higher mono-benzyl phthalate concentration was associated with a higher risk of delayed puberty in girls (OR = 2.75, 95% confidence interval: 1.34, 5.66). In the mixture exposure models, exposure to a mixture of BPA and phthalate metabolites was associated with precocious puberty in boys and delayed puberty in both sexes, although the risk estimates were imprecise. Our findings add to the increasing evidence suggesting that exposure to environmental chemicals may contribute to delayed puberty.